This invention relates to an improved granulate enzyme composition and to a process for making same. The improved granulate enzyme composition has improved stability when mixed with a peroxyacid bleach granulate.
During the last score of years the use of enzymes, especially of microbial origin, has been more and more common. Enzymes are used in, for example, the starch industry to produce glucose and fructose by means of amylases, amylglucosidases and glucose isomerases. In the dairy industry a vast tonnage of rennets is used and in the detergent industry proteases are normally used as additives in the washing powders to impart a better action on proteinaceous stains on the laundry.
On July 7, 1970, C. B. McCarty was granted U.S. Pat. No. 3,519,570 for enzyme-containing detergent compositions and a process for conglutination of enzymes and detergents.
U.S. Pat. No. 3,784,476, van Kampen et al., issued Jan. 8, 1974, discloses a particulate enzyme-containing detergent composition containing a detergent surface-active agent, a water-soluble builder salt and discrete, shaped inorganic solids containing proteolytic or amylolytic enzymes. It should be noted that this patent does not teach an enzyme core coated with an alkaline buffer salt as disclosed herein.
U.S. Pat. No. 4,106,991, Markensen et al., issued Aug. 15, 1978, incorporated herein in its entirety, discloses an improved formation for enzyme granulates through inclusion within the composition of finely divided cellulose fibers. Optionally a waxy substance can be employed for the granulating agent, or to coat the granulate. This patent claims a granulate composition comprising enzyme, inorganic salts, a granulation binder, and finely divided cellulose fibers as 2-40% by weight of the granulate.
Making a storage stable mixture of enzyme containing granulates and dry peroxyacid bleach granulates is a difficult task. In spite of the fact that some commercially available enzyme granulates are advertised as "perborate bleach stable," they are weak storagewise in the presence of strong peroxyacid bleach granulates. It should be noted that peroxyacid bleach granulates are relative newcomers to the dry commercial laundry detergent and bleach markets. The term "bleach" as used herein unless otherwise specified means peroxyacid bleach and the terms "peroxyacid bleach powder" and "peroxyacid bleach granulates" are synonymous unless otherwise specified.